Sex triggers the same neurochemicals to the same degree in the brain that food, water, breathing and exercise do.  Relative to the human experience, "sex" can be used in our everyday for categorizing actions taken towards the fullfilment of desire.

     Sex is a process.  Once we remove sex from subjective emotion (ie making love) you are able to view it as an act, with a procedure motivated from libidinal motivation.  Libido also refers to a larger subject base then the want for anal, vaginal, or oral consummation.  Libido, much like lust, can refer to and strong desire for anything.  For example, you can lust after a car.  You can then go out and test drive the car, and be satisfied by its purchase.  That could be considered a sexual act.  Desire leads to action, which leads to climax (the point where action no longer needs to be taken) and the end. 

     Yes, you could say that I am equivocating on the term sexual, or that this is a very reductionist view, but with further insight you learn that your brain interprets these non-consummatory acts in the same manner.

     The neurochemicals with which your brain produces happiness, elation, pleasure and satisfaction are the same regardless of the methods employed to trigger them.  Dopamine, Seratonin, Endorphins, and Andrenaline (to name a few) are major chemicals associated with the above states.  -Dopamine, among its other functions, is what makes drugs so appealing (hence the term "dope").  Most commonly associated with chemical elation, it acts as an emotional intensifier, responsible for hightened sensation.  Dopamine is felt strongly through orgasm, and orgasm actually releases and triggers manufacture of dopamine.  Food similarly reacts with dopamine, sometimes to a lesser extent (foods like chocolate, and overeating are famous for their dopamine rushes).  -Seratonin is most commonly associated with either depression or mania.  In fact, the term depression may specify  a depressed level of seratonin in the brain.  Seratonin has been directly linked to sex drive; seratonin also increases in the brain post-orgasm.  Runner's high can be associated with seratonin (as well as dopamine) because it is a function of occupatory succes; depression, psychologically is a lack of attaining the object of desire, runners in this instance make a connection to their 'object' through running.  -Endorphins are very sexually linked for the reason that the easiest way to release them is by dermal, or tactile stimulation.  Domestic animals like to be petted because their hair folicles are embedded in their skin, and the stimulation releases endorphins.  Endorphins are also and emotional intoxicant.  Sexual incounters, for this reason, involving seductive, even minor touching, or light touching in foreplay etc.  will cause a major release of endorphins, depending on your level of emotional involvement.  Endorphins can even explain why some foods or more pleasurable than others.  There are three parts to the taste function, 1/3 taste bud reaction, 1/3 smell, and 1/3 texture, so some foods will trigger endorphin release due to their texture and the person's eating technique, and others will not.  This touch-sensitive neurochemical helps us view skin as inherently sexual, the prime example being showering.  -Andrenaline is a very interesting chemical, it being produced by its own gland and typically concerning rage, anger, and fear.  Extreme sports, risk taking, near death experiences, heavy physical activity etc are all things which trigger adrenaline.  Adrenaline is also associated with the fight or flight fear response.  Pain and fear both demand adrenaline, and are both naturally associated with the consummatory sex act.  Pain, being a form of dermal stimulation, can demand adrenaline and thusly "pump you up" for an upcomming activity.  Athletes demonstrate adrenaline uses when  they smack themselves, pound their chest, yell at one another, or do high impact warm ups.

     There are mutliple levels to human existence; mind, body, spirit.  It is ridicualour to assume that human experiences are not likewise multitiered.  Physical sex, genital and conssummatory are just one level: BODY.  Psychologically speaking, other things can react sexually or trigger sexual desire.  Spiritually, it is the same.  Anything that can be romanticized is sexual in nature, so why can't the activity of doing it be considered sex?  Receiving the Eucharist is a good example.  Here, you are taking the body and blood of one you 'love' and who 'loves' you,  into your body, and are thusly transformed by this transubstantiation, made to feel as though you belong and are special.  There is a high reported frequency of a euphoria experienced in believers.  Could this be a more concrete non-consummatory example of glorified sex?

     The fact is, there are a whole lotta people out there and each of them can get off doing different things.  Anything stimulating to you metnally, physically, spiritually, emotionally etc.can be "sexually" arousing.  Additionally sex as we know it, is just our way of defining a template for the procedure in our actions towards gratification.  Sex need not be narrowed to copulation and fornication alone, because sex is a process that we utilize in every area of our lives.  Sex is an adverb, adjective, noun, and verb so why not allow it to expand into those general terms?  Want, Seek, Act, Acquire, Satisfy; the basis of almost all human activity, sexcual intercourse included.  Things we do can be broken down to desire, and any action motivated by that desire to acheive a certain end are sex.  Successful ends in our life are orgasms when we accept our innately romantic nature.

     This does not mean that we are sex obsessed.  Somply, it means that sex is a classification for desire based acitivty, genital or otherwise.  We are all romantics, and this view is modern romanticism.  When we develop a new way to exist, then our "sex" may become obsolete.  Until then, the rituals we undertake in our life, and to those we assign higher value are all connected by one thing: our desire.  Desire can uplift us and it can degrade us, it's all in the outlook, interpretation and our own assigned definitions.